|Cheapest bid over the overcall||2 aces|
|Second-cheapest bid||3 aces|
|Third-cheapest bid||4 aces|
If playing Roman Key Card Blackwood, the responses are:
|Double||0, 3 or 5 keycards|
|Pass||1 or 4 keycards|
|Cheapest bid over the overcall||2 keycards without the trump queen|
|Second-cheapest bid||2 keycards with the trump queen|
If partner bids 4NT followed by 5NT, he is making a Blackwood query for kings. All other rebids by partner are natural signoffs.
DOPI is more informative than DEPO, but the drawback is that it can't be played when the opponents compete above 5 of your trump suit. For example:
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